<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://cdn.jsdelivr.net/npm/vue@3.2.38/dist/vue.global.min.js"></script>
  <style>
    span {
      margin: 0 10px;
    }

    .isActive {
      background-color: red;
    }
  </style>
</head>

<body>
  <div id="app">
    <span v-for="(item,index) in movieList" :class="currentId === index ? 'isActive' : ''" @click="change(index)">
      {{item}}
    </span>
  </div>
</body>
<script>
  Vue.createApp({
    data() {
      return {
        currentId: 0,
        movieList: ['教父', '阿甘正传', '楚门的世界', '盗梦空间']
      }
    },
    methods: {
      change(index) {
        console.log(index)
        this.currentId = index
      }
    }
  }).mount('#app')
</script>

</html>
